The Johns Hopkins Gazette: June 5, 2000
June 5, 2000
VOL. 29, NO. 38


NEAR Shoemaker Observations Link Eros to Primordial Solar System

Johns Hopkins Gazette Online Edition

New data from NASA's Near Earth Asteroid Rendezvous mission indicate asteroid Eros may be a primordial relic left over from the solar system's formation. Using the X-ray/Gamma-ray Spectrometer on the NEAR Shoemaker spacecraft, scientists will spend the remainder of the mission collecting data from other parts of Eros to determine if their latest findings are consistent across the approximately 21-mile-long asteroid. If they are, studying Eros should help scientists understand how the rocky planets evolved.

The Applied Physics Laboratory designed and built the NEAR spacecraft and manages the mission for NASA.

The NEAR team gathered the information after a powerful explosion on the sun zapped Eros with X-rays on May 4. The half-hour solar flare caused elements on Eros' surface to emit X-rays, a type of radiation invisible to humans. Instruments on NEAR Shoemaker analyzed the intensity of X-rays produced by the asteroid at different wavelengths, getting a fingerprint of the asteroid's chemical composition.

"Analysis of X-rays from an area roughly 3.7 miles across on Eros indicates it has an elemental composition similar to the most primitive rocks in the solar system, the chondritic meteorites," says Jacob Trombka of NASA's Goddard Space Flight Center, who heads the XGRS instrument team. Trombka presented the result May 30 during the American Geophysical Union's spring meeting in Washington, D.C.

"Chondrites are the building blocks of terrestrial planets," says Tim McCoy of the Smithsonian Institution's National Museum of Natural History, a participating scientist on the XGRS team. "If more data confirm Eros is primordial, Eros will be a link between the chondrite meteorites found on Earth and the history of the solar system's formation. With Eros, we could be looking at the structure of the solar system during a time no longer recorded on Earth."

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